A Comprehensive Guide to Aluminum PCBs

guide to aluminum pcbs

If you were to google Aluminum PCBs, you would get over 23 million results. So, yes, calling them the most common, and most popular, printed circuit board option would definitely be an understatement. Even if there are other options out there, such as copper PCBs, they are not only less popular than the aluminum boards, but their performance also tends to be lacking in comparison. In short, everyone seems to want to get their hands on these products, from regular consumers to retailers and manufacturers.

But why is that? Why are these types of PCBs so popular nowadays? In this article, I will attempt to answer that question. By the end of it, you’ll know everything there is to know about aluminum printed circuit boards, as well as why everyone wants them.

What Is an Aluminum PCB?

As its name suggests, this board contains a noticeable amount of aluminum. Generally, this type of PCBs consists of three different layers:

  • Layer #1 contains a copper foil, etched to form a printed circuit
  • Layer #2, the dielectric layer, contains aluminum which acts as a thermal barrier between the other two layers
  • The final layer is the metal base, usually aluminum due to its heat dissipation capabilities

You etch the copper layer into the dielectric panel, forming the type of circuitry your PCB needs. On the other hand, the third layer is there to draw away the heat from the board, dissipating it.

Standard FR-4 boards used to be the go-to choice for any IT firm worth its salt. However, when it comes to performance, pricing, and longevity, they have been sidelined by the superior aluminum PCBs. As flame-retardant as glass-reinforced epoxy resin laminate might be, it still pales in comparison to the superior heat-reducing capabilities of the metal.

Of course, there are different types of aluminum PCBs, and they all come with their set of pros and cons. So, let’s see what kind of boards you can make using this thin, heat-dispersing metal.

Classification of Aluminum PCBs

Flexible PCBs

A typical dielectric layer of a flexible aluminum PCB contains a polyimide resin system with ceramic fillers. Not only will these materials provide excellent insulation, but their thermal conductivity is at the very top.

However, the biggest advantage of a flexible PCB is just that — flexibility. Instead of installing fixtures, connectors, and cables (which cost money), you can literally bend the product into any shape you need. Of course, even if they are flexible, they will stay in place once you bend them.

Hybrid PCBs

How can you get the best of both non-thermal material and a metal base when making a circuit board? The answer is simple — just combine the two.

Hybrid PCBs are the result of a thermal fusion between the metal base and material that doesn’t conduct heat. Usually, this material is processed independently, as a part of a sub-assembly. More often than not, experts will use either a 2-layer or a 4-layer FR-4 to do the trick.

When bonded with the base using thermal dielectrics, this type of PCB has lots of advantages and benefits, including:

  • Spectacular heat dissipation
  • Superior thermal performance to a standard FR-4
  • Low-cost manufacturing
  • Aluminum component windows can accommodate through-hole board components.

Through-hole PCBs

Sometimes, the metal itself can act as the core of a thermal construction with multiple layers. However, the process itself is a bit long and complicated. Here are the key steps:

  • Experts pre-drill the metal
  • They back-fill the dielectric before the lamination
  • Both thermal materials and sub-assemblies also go through detailed lamination
  • The experts then thru-drill the assembly
  • Plated through-holes go through the clearances in the metal, maintaining electrical insulation (hence the name)

Multilayer PCBs

Layers of different dielectrics can provide extra thermal conductivity to these PCBs. Normally, a multilayer construction has several levels of circuitry, with each of them conducting heat properly. These types of boards usually cost a lot of money and users opt for one of the other 3 types of PCBs I listed. However, a multilayer PCB is the best kind of heat dissipator you can use in a complex design.

The Applications of Aluminum PCBs

Since these PCBs are a low-cost solution with the best heat dissipation out there, it’s no wonder that so many people want to use them in place of traditional boards. In fact, they have a wide range of applications across different industries. So, let’s go over a list of examples where you can use an aluminum circuit board.

LED Circuit Boards

LED PCBs have become incredibly popular lately. Not only do they provide an amazing lighting output, but they do it by saving energy and having a long lifespan, longer than any other current light source used by modern tech.

Of course, having an LED fixture on a circuit board can be dangerous, since overheating might affect the circuitry and damage it. For that reason, you need a way to dissipate all of that heat. And by far, the best way to do it is to have dielectric layers of your PCBs made of aluminum.

Automotive Industry

Normally, the LED PCBs and the automotive industry are tightly connected, but there are other areas in modern cars where you can use a non-LED circuit board.

But no matter where you use them, these types of boards are perfect for the current automotive industry. The fact that they can disperse heat easily makes them ideal for spaces that are regularly under high temperatures. In addition, this type of PCB can be big or small, solid or flexible, making it your go-to choice when it comes to car adaptability.

Consumer Products

As I stated earlier, these PCBs vary greatly in size, shape, and intensity. In other words, they are almost tailor-made for modern consumer electronics. On the one hand, you can use them in common light sources, such as street lights, traffic lights, camping gear, landscape lighting, and even interior building lights. On the other hand, you can find these PCBs in modern-day PCs and laptops.

Motor Drives

Industrial motor drives are incredibly necessary for our modern world to function. And in order for them to have the best output, they need PCBs with good heat dissipation and a long lifespan, i.e. they need aluminum PCBs.

Lots of circuit boards for motor drives need to meet specific operating parameters and pass certain safety tests. Luckily, an average board usually passes all of those with flying colors due to its impeccable performance, as well as a low production cost.

Solid-state Relays

A solid-state relay, or SSR, is a type of device that switches on and off when you apply either AC or DC to its control terminals. Unlike regular relays, the SSR has no moving parts, so it usually has a long operational lifetime.

Because of what you use it for, you can expect an SSR to either overheat or underperform. That’s why it’s vital that your SSR contains this type of PCB in order to dissipate the heat and allow it to run smoothly.

Advantages of Aluminum PCBs

Weight

Aluminum is quite a durable metal, which I’ll get into shortly. And as a durable metal, you’d think that it would need to have some weight to it. However, it’s the exact opposite — aluminum is one of the most lightweight metals that we use regularly. That makes it perfect for small consumer electronics since it doesn’t weigh the products down but still manages to endure any serious damage.

Durability

Having a ceramic or a fiberglass PCB base is all fine and good, but in terms of how durable they are, those materials are at the bottom of the list. Aluminum, on the other hand, is sturdy and durable. It’s highly unlikely that you will see a crack form anytime soon, whether the product has just come out of assembly or has been inside of your appliance of choice for years.

Heat Dissipation

By far, the biggest problem every single PCB manufacturer faces is how the unit will handle high temperatures. After all, some of the circuitry is so small and fragile that it could suffer a lot of damage as the board is being used.

That’s why using aluminum as a dielectrics component is genius. The metal is excellent at dissipating heat that comes from the circuitry, letting it disperse and allowing each circuit to work normally even under intense circumstances.

Environmentally Friendly

These types of PCBs don’t take too long to assemble, meaning you get to save energy and money while assembling them. In addition, the metal itself is a material which you can recycle, so by using (and reusing) it, you’re effectively saving the planet from pollution.

Low Cost

Since aluminum is a metal you can literally find anywhere on the planet, the price of mining and refining it is low, as is the cost of manufacturing the circuit boards themselves. And if you were to mass-produce these PCBs, you’ll earn even more money by selling the units at prices that are lower than your initial PCB series.

Selecting the Best PCB Manufacturer

Now that you know a fair bit about PCBs, you might be interested in either manufacturing or selling them. Whatever option you decide to…well, opt for, you will need to know what makes a decent PCB manufacturer. So, when seeking out the best, keep these details in mind at all times:

  • The manufacturer must have dedicated imaging equipment
  • It must also have the proper equipment for V-scoring
  • Their punch presses must have a tonnage that goes over 40 t
  • The PCBs must all pass the HIPOT test.

As a manufacturer, by considering these details, you will always manufacture the best PCBs on the market. Alternatively, if you decide on selling these PCBs, always make sure that the manufacturer you’re working with is legitimate. The market is being flooded with new PCB brands every single day, so it’s hard to keep track of everyone, legitimate or otherwise.

Final Thoughts on Aluminum PCBs

And there you have it. When it’s all said and done, aluminum PCBs have a lot of advantages over other types of printed circuit boards. And with the technology growing rapidly every day, consumers will need all the durable, heat-conductive, low-cost PCBs they can get.

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